Could either of these things have happened?
1/ two taps of A/T instead of one? Yip.
2/ A whole handful of thrust if A/T not engaged? Yip.
So a simple error ( either 1 or 2) and you now have a lite NG with full power climbing into an increasing headwind at 4am with a crew who has been airborne for six hours, one of whom allegedly resigned due fatiguing rosters.
It is not difficult to imagine how the above situation is only a few moments of brain-fart away from tragedy.
So if this turns out to be the case, what should be done?
Regulate to ensure our Airline crews aren't rostered to the point of fatigue.
They should be the opposite. Mentally fit, well rested, well trained.